Phenol recovery process



Jan. 1, 1935. c. L. BURDICK 1,986,320

. PHENOL RECOVERY PROCESS Filed Dec. 11, 1951 Plmnol Conl'aininq LiquorExlracl'ecl Wlll'l Wa'lcr lmmisciblo Alcohols v Exlracled Liquor l0WZLSl c I E Phenol-Alcohol ExTracT Dcphcnolizcd scrubbed Wlll'l CausTucAlcohol Trealmcnl'of Sodium Phenolale Willi CQ,or Dilul'c Acid Phcmol IN VEN TOR.

Charles l... BurclicK TORNEY.

Patented Jan. 1935 I 1,986,320

UNITED STATES PATENT OFFICE.

1,988,320 rumor. aaoovaax raocass curler L. Burdick, Wilmington, DeL,assignor to E. I. (In Pont de Nemonrs as Company, Wilmington, DeL, acorporation of Delaware Application December 11, 1931, Serial No.580,281

9 Claims. (CL 260154) This invention relates to a process for therehols, which are obtained by the catalytic hydrocovery of phenols fromsolution and more particugenation of carbon oxides under elevatedpreslarly to a process for the recovery of phenols by sure as described,for example, in Roger Williams extraction from gas liquor by means ofwater U. S. Patent No. l,820,4l7,-the fractions boiling v insolublealcohols. in the range of 130 to 210 C. being especially 5 Theby-product coke industry, at the present eillcient. s time, isconfronted with a most diflicult problem It is common to treatphenol-bearing liquors as respects disposal of the liquor produced inthe with benzol, which is immiscible therewith and recovery of ammoniafrom such processes. This ,which extracts the phenol. This extraction isliquor is variously called gas liquor, ammonia ilsually practiced on theundistilled ammoniacal 10 liquor, etc. Many producers in the industryliquors. The phenol is then removed from the would like to rim thiseilluent to waste and altho benzol, by treatment with a caustic sodasolution, the ammonia it contains is quite harmless,-its thus formingsodium phenolate, and the'phenol phenol content, on the other hand, isoften in is subsequently separated by acidification, or

1 sumcient concentrationto give considerable troutreatment with carbondioxide. The extraction l5 ble when discharged into the neighboringstreams. of phenol-bearing liquids with water immiscible The publichealth and game conservation authori alcohols, and more particularlytheir extraction ties generally r8158 l et 6 89 8 0! it. with mypreferred mixture of water immiscible in this manner, due to the toxiceffect and the alcohols, is carried out in much the same manner 2unpleasant taste imparted by the phenols to the as the extraction ofphenol with benzol.

' water. I A general method, which is susceptible of many It would,therefore, be of considerable advanmodifications, is as follows: A flowsheet for this tage to this industry'to be provided with asimple generalmethod accompanies this specification, and inexpensive process whichwould enable the and, by reference to it, the steps of my process cokeOv n p rator to eliminate phenols from the may be more readily andclearly understood. The 25 gas liquor. Hev would then be free todischarge liquor, containing phenols, such as that obtained this liquorinto the neighboring streams without inthe treatment of liquors producedin the reh ndrance from the authorities or ncroa hment covery or ammoniafrom coal gas, is extracted upon the riparian rights of others. with oneor more water immiscible alcohols. The

An object 0! the present invention 18 to P ovide I water immisciblealcohol ispreferably introduced 30 a process for e re ov y o phe ols, csol. a d in a finely divided state into the liquid. The like 1181' acidsfrom 8 q ammo ia q alcohols in this form may be forced into the etc- A oer object of t e invention is to probottom of a packed column, which isfilled with v d a ocess fo he recove of phenols f om the alcohol andliquor, down which the am- 86 s liquor by extraction i a water i is i emoniacal liquor is flowing. Any other suitable as alcohol. A furtherobject of the invention is to type of extracting apparatus may, ofcourse, be Provide a ess the act on of aqueous used. The alcohols beingof a lighter specific phenol-be i s utions by means or a mixture gravitythan the liquor bubble up thru it and in Of Wa immiscible oxygenatedOrganic doing so efilciently extract the phenol from the 40 p u ds o aed by the ydro ation o c bon liquor; From the top of the tower thephenol- 40 oxides under elevated pressure. Other objects charged-alcoholis withdrawn, while from the and advanta e f th ent on will be mo ebottom the liquor which is now substantially free readily u de tood f efo wi spec flrrom phenol is passed to waste. The alcoholcation. 1 phenolmixture is now scrubbed with an aqueous 46 Ihave found t ph o nd li ecomcaustic soda or similar alkaline solution which p ds vi imisolubility c aract ristics, converts the phenol present to sodiumphenolate. may be ext acted fro solutions a d ore per- From thescrubbing operation, the alcohols, free tlcllla y 1mm a a andphenol-containin from thephenols, are returned to the extraction 8liquor y extraction with a Water immiscible operation. The aqueouscaustic soda and sodium 50 alcohol, such, for examp as b y 81001101. yphenolate solution is treated with dilute acid or 50 alcohol, hexylalcohol, etc. A mixture of these preferably carbon dioxidewhichdecomposes the water immiscible alcohols may likewise be emsodiumphenolate it contains and allows the ployed and I prefer to employ moreparticularly phenol to form aseparate layer. 7 l the water immisciblefractions of the oxygenated An alternate method of effecting theextraction organic compounds, comprising essentially alcomay be carriedout in accord with the following 55 process. In lieu of introducing thealcohols into a packed column as described above, they may be sprayedinto a tank containing the alcohol mixture. The tank, if desired, may beone of a series. The liquors, discharged from the bottom of the firsttank, are sprayed into a second tank containing the alcohol mixture,less saturated with the phenols extracted than the first mixture. Toobtain substantially complete extraction additional stages may be used.When the alcohols in the first stage have reached substantialsaturation, they are discharged and the phenol-alcohol extract treatedas described above for the recovery of the phenol and purification ofthe alcohols. The first stage is then recharged with the dephenolizedalcohol mixture and used as the last extraction stage from the bottom ofwhich the extracted liquor is passed to waste.

The extracting and scrubbing operations may be conducted to advantage byforcing the alcohols 'or' liquor and caustic, in their respectiveoperations, .thru a porous medium, such as the well known Filtros blocksor plates, alundum plates, fabric diffuses, or the like, thru which thematerials are introduced, in a minute state of subdivision, into theliquid being treated. Such treatment greatly increases the efiiciency ofthe respective extracting and scrubbing operations. A similar type ofapparatus may also be employed, if desired, for the treatment of theaqueous sodium phenolate solution with either carbon dioxide or diluteacid.

While the individual water immiscible alcohols, such as thosespecifically designated above, are well suited for extractingphenol-bearing liquors,

"I prefer a, mixture of these alcohols such as is obtained by thecatalytic hydrogenation of carbon oxides under pressure. Accordingly, inpreparing my' preferred alcohol mixture I subject the mixture ofoxygenated organic compounds obtained in high pressure catalytichydrogenamore fully appreciated, its ability to extract phenol fromliquors has been compared with the ability of benzol underidenticalconditions. An ammoniacal liquor containing 6.3 grams of phenolper liter was extracted with this alcohol mixture. The alcohol prior'tothe extraction contained no phenol. After extraction the ammoniacalliquor contained approximately 0.66grams of phenol per liter, while thealcohol contained 5.8 grams of phenol per liter. These are averagevalues obtained from several runs. In the comparative runs with benzolthe ammoniacal liquor after extraction contained approximately anaverage of 3.5 grams of phenol per liter while the benzol contained anaverage of 2.8 grams of phenol per liter. The benzol, initially,contained no phenol.

disregarding the possibility of association of the phenol in eitherextracting medium, it has been found that the best average values of thepartiit will be realized that any modification of my method of treatingaqueous phenol-bearing liquors with water immiscible alcohols, and moreparticularly with my preferred mixture of water immiscible alcohols,will come within the scope of this invention without sacrificing any ofthe advantages that may be derived therefrom.

Iclaim:

. 1. In a process of treating a phenol-bearing liquor for extraction ofphenol therefrom, the step which comprises treating the liquor with amixture of water immiscible phenol-absorbing oxygenated organiccompounds obtained from the catalytichydrogenation of carbonoxides underelevated temperatures and pressures.

, 2. In a process of treating a phenol-bearing liquor for extraction ofphenol therefrom, the step which comprises treating the liquor with amixture of the synthetic aliphatic: alcohols boiling within the range ofapproximately 130-210" 0. obtained by the hydrogenation of carbon oxidesunder elevated pressure.

3. In a process of extracting phenol from a phenol-bearing liquor, thestep which comprises subjecting the liquor to extraction with a syn-jthetic aliphatic alcohol fraction boiling within the range ofapproximately 130-210" C. obtained by the hydrogenation of carbon oxidesunder elevated pressure.

4. In a process of extracting phenol from a phenol-bearing liquor, thestep which comprises subjecting the liquor to extraction with a mixtureof water immiscible synthetic aliphatic alcohols obtained from thecatalytic hydrogenation of carbon oxides under-elevated pressure.

5. In a process of extracting phenol from a phenol-bearing liquor, thestep which comprises subjecting the liquor to extraction with anextractant containinga plurality of compounds obtained from a mixture ofoxygenated organic compounds, having the boiling range of fromapproximately 130-210 0., obtained by the hydrogenation of carbon oxidesunder elevated pressure.

6-. In the treatment of gas, liquor to remove phenol therefrom, the stepwhich comprises treating the liquor with a mixture of syntheticaliphatic alcohols boiling within the range of approximately 130-210 0.,obtained by the hydrogenation of carbon oxides under elevated pressure,

the alcohols being supplied to the liquor in a finely divided state.

I 7. The process for the removal of phenols from gas liquor whichcomprises subjecting the gas liquor to treatment with a mixture ofsynthetic aliphatic alcohols boiling within the range of approximately130-210 (3., obtained by the hydrogenation of carbon oxides underelevated pressure, scrubbing the alcohol-extract therefrom with causticalkali, to convert the phenols it contains to sodium phenolate, andsubsequently reconverting the sodium phenolate to phenol.

-8. The process of removing phenol from gas liquor which comprisesextracting the gas liquor by means of a mixture of synthetic aliphaticalcohols boiling within the range of approximately -210 0. obtained bythe hydrogenation of carbon oxides under elevated pressure, theextraction being conducted by passing the alcohols countercurrent to theflow of the gas liquor, scrubbing the alcohol-extract with caustic soda,re-

turning the alcohols separated during the sembbing operation to theextracting operation, treating the aqueous sodium phenolate solution,

formed during the scrnbbinz operation, with cartherefrom by extractingwith a mixture or oxybon dioxide whereby the sodium phenolate isreaenated organic compounds boiling within the converted to phenol, andsubsequently separating range oi! approximately 130-210 0. obtained bythe phenol. the hydrogenation of carbon oxides under elevat- 5 9. Theprocess 01' treating aqueous phenoled pressure.

ing liquor which comprises separating the phenol CHARLES L. BURDICK.

